Round tungsten beads for bead-head nymphs and wet flies. Sized true, drilled clean, and weighted the same bead to bead, so the head of the fly is the part you never have to think about.
95% tungsten alloy, about 18 g/cm³, roughly 1.6 times the density of lead. Sizes run 2.0mm to 4.5mm, covering midge bead-heads up through large stonefly and attractor nymphs. Solid finishes come in 23 colors. Speckled comes in 11 colorways, worth reaching for on pressured water where a polished bead reads as a bead and a mottled one reads as part of the insect.
Round beads want a straight or lightly bent shank. They will not clear the bend on a jig hook, which is what slotted beads are for. Pair with Firehole Sticks nymph hooks and the bead and the wire gauge are matched from the start.